﻿APR. 
  4, 
  1922 
  brouwBr: 
  tectonic 
  features 
  dutch 
  east 
  indies 
  181 
  

  

  proof 
  of 
  recent 
  upheaval 
  of 
  the 
  land, 
  while 
  the 
  deep-sea 
  chart 
  shows 
  a 
  

   complicated 
  topography 
  to 
  the 
  south 
  of 
  Java 
  and 
  Sumatra. 
  That 
  

   these 
  movements 
  still 
  continue 
  is 
  proved 
  by 
  the 
  distribution 
  of 
  earth- 
  

   quakes 
  in 
  the 
  Archipelago. 
  In 
  the 
  region 
  including 
  eastern 
  Sumatra, 
  

   the 
  southern 
  China 
  Sea, 
  northern 
  Java, 
  and 
  Borneo, 
  heavy 
  tectonic 
  

   earthquakes 
  are 
  practically 
  absent. 
  The 
  shocks 
  felt 
  in 
  this 
  area 
  have 
  

   their 
  origin 
  in 
  the 
  mobile 
  areas, 
  which 
  are 
  as 
  a 
  rule 
  submarine, 
  as 
  shown 
  

   by 
  the 
  seismic 
  epicenters. 
  

  

  The 
  large 
  bendings 
  in 
  the 
  mountain 
  chains 
  of 
  recent 
  age 
  in 
  the 
  

   southern 
  and 
  eastern 
  parts 
  of 
  the 
  Archipelago 
  are 
  clearly 
  visible 
  on 
  the 
  

   deep 
  sea 
  chart 
  of 
  the 
  region. 
  But 
  if 
  considered 
  in 
  detail 
  it 
  is 
  obvious 
  

   that 
  important 
  bendings 
  of 
  smaller 
  amount 
  are 
  numerous. 
  They 
  are 
  not 
  

   always 
  clearly 
  visible 
  in 
  the 
  present 
  topography, 
  because 
  many 
  of 
  the 
  

   bending-points, 
  which 
  are 
  the 
  loci 
  of 
  considerable 
  transverse 
  fractures, 
  

   are 
  covered 
  by 
  the 
  sea. 
  Examples 
  of 
  this 
  kind 
  are 
  the 
  narrow 
  Manipa 
  

   Strait 
  between 
  Ceram 
  and 
  Buru, 
  nearly 
  5,000 
  M. 
  deep, 
  the 
  strait 
  be- 
  

   tween 
  Timor 
  and 
  Rotti, 
  the 
  strait 
  between 
  Timor 
  and 
  the 
  Sermata 
  

   islands, 
  and 
  Sunda 
  Strait 
  between 
  Java 
  and 
  Sumatra. 
  In 
  the 
  row 
  of 
  

   islands 
  from 
  Nias 
  to 
  Enggano, 
  to 
  the 
  west 
  of 
  Sumatra, 
  several 
  examples 
  

   of 
  this 
  kind 
  also 
  occur. 
  

  

  tertiary 
  strikes 
  are 
  cut 
  obliquely 
  by 
  the 
  present 
  geanticeinal 
  

  

  AXES 
  

  

  The 
  establishment 
  of 
  the 
  fact 
  that 
  Tertiary 
  strikes 
  are 
  cut 
  obliquely 
  

   by 
  the 
  present 
  geanticlinal 
  axes 
  is 
  of 
  great 
  importance 
  for 
  a 
  precise 
  

   understanding 
  of 
  the 
  mountain-building 
  process. 
  Several 
  exam-ples 
  

   are 
  known 
  in 
  the 
  Dutch 
  East 
  Indies. 
  On 
  the 
  south 
  coast 
  of 
  Timor 
  

   the 
  strike 
  of 
  the 
  Jurassic 
  and 
  Cretaceous 
  strata 
  of 
  the 
  Amanuban 
  

   mountain 
  chain 
  differs 
  about 
  12° 
  from 
  the 
  general 
  trend 
  of 
  the 
  coast 
  

   line. 
  The 
  high 
  mountain 
  range 
  of 
  central 
  Ceram, 
  in 
  which 
  the 
  Meso- 
  

   zoic 
  and 
  Tertiary 
  strata 
  strike 
  about 
  NW-SE, 
  is 
  cut 
  off 
  abruptly 
  at 
  the 
  

   coast 
  with 
  a 
  general 
  E-W 
  trend. 
  The 
  abnormal 
  strike 
  in 
  the 
  eastern 
  

   peninsula 
  of 
  Celebes 
  and 
  in 
  the 
  narrow 
  portion 
  which 
  connects 
  the 
  

   central 
  part 
  of 
  the 
  island 
  with 
  the 
  northeastern 
  peninsula 
  have 
  been 
  

   already 
  mentioned. 
  Another 
  noteworthy 
  example 
  is 
  on 
  the 
  island 
  

   Babber 
  to 
  the 
  east 
  of 
  Timor, 
  where 
  the 
  strike 
  is 
  NNE-SSW, 
  nearly 
  

   perpendicular 
  to 
  the 
  main 
  trend 
  of 
  the 
  present 
  row 
  of 
  islands. 
  

  

  Similar 
  facts 
  are 
  well 
  known 
  from 
  Japan. 
  Von 
  Richthofen 
  believed 
  

   the 
  formation 
  of 
  the 
  arcs 
  to 
  be 
  due 
  to 
  a 
  rupture 
  (Zerrung) 
  caused 
  

   by 
  the 
  subsidence 
  of 
  the 
  oceanic 
  side, 
  and 
  denied 
  the 
  existence 
  

  

  